Clothing with enhanced response characteristics for laser finishing

ABSTRACT

A fabric has enhanced response characteristics for laser finishing. The fabric can be denim for denim apparel such as jeans. Software and lasers are used to finish apparel made of the fabric to produce a desired wear or distressing pattern or other design. The fabric allows for relatively fast color change in response to the laser, color changes in hue from indigo blue to white, many grayscale levels, and maintains strength and stretch properties. A method used to make the fabric includes spinning, dyeing, and weaving yarns in such a way to obtain the desired enhanced response characteristics for laser finishing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims the benefit of U.S. patent application62/433,739, filed Dec. 13, 2016, which is incorporated by referencealong with all other references cited in this application.

BACKGROUND OF THE INVENTION

The present invention relates to textiles and, more specifically, tomaterials and fabrics and their manufacture, in which the materials andfabrics will have enhanced response characteristics for laser finishing,especially for denim and denim apparel including jeans, shirts, shorts,jackets, vests, and skirts, to obtain a faded, distressed, washed, orworn finish or appearance.

In 1853, during the California Gold Rush, Levi Strauss, a 24-year-oldGerman immigrant, left New York for San Francisco with a small supply ofdry goods with the intention of opening a branch of his brother's NewYork dry goods business. Shortly after arriving in San Francisco, Mr.Strauss realized that the miners and prospectors (called the “fortyniners”) needed pants strong enough to last through the hard workconditions they endured. So, Mr. Strauss developed the now familiarjeans which he sold to the miners. The company he founded, Levi Strauss& Co., still sells jeans and is the most widely known jeans brand in theworld. Levi's is a trademark of Levi Strauss & Co.

Though jeans at the time of the Gold Rush were used as work clothes,jeans have evolved to be fashionably worn everyday by men and women,showing up on billboards, television commercials, and fashion runways.Fashion is one of the largest consumer industries in the U.S. and aroundthe world. Jeans and related apparel are a significant segment of theindustry.

As fashion, people are concerned with the appearance of their jeans.Many people desire a faded or worn blue jeans look. In the past, jeansbecame faded or distressed through normal wash and wear. The apparelindustry recognized people's desire for the worn blue jeans look andbegan producing jeans and apparel with different wear patterns. The wearpatterns have become part of the jeans style and fashion. Some examplesof wear patterns include combs or honeycombs, whiskers, stacks, andtrain tracks.

Despite the widespread success jeans have enjoyed, the process toproduce modern jeans with wear patterns takes processing time, hasrelatively high processing cost, and is resource intensive. A typicalprocess to produce jeans uses significant amounts of water, chemicals(e.g., bleaching or oxidizing agents), ozone, enzymes, and pumice stone.For example, it may take from about 20 to 60 liters of water to finisheach pair of jeans.

Therefore, there is a need for an improved materials and fabrics forlaser finishing of jeans and other apparel that reduces environmentalimpact, processing time, and processing costs, while maintaining thelook and style of traditional finishing techniques.

BRIEF SUMMARY OF THE INVENTION

A fabric has enhanced response characteristics for laser finishing. Thefabric can be denim for denim apparel such as jeans. Software and lasersare used to finish apparel made of the fabric to produce a desired wearor distressing pattern or other design. The fabric allows for relativelyfast color change in response to the laser, color changes in hue fromindigo blue to white, many grayscale levels, and maintains strength andstretch properties. A method used to make the fabric includes spinning,dyeing, and weaving yarns in such a way to obtain the desired enhancedresponse characteristics for laser finishing.

In an implementation, an article of clothing includes: a fabric withindigo ring-dyed yarn; and a finishing pattern on the fabric. Thefinishing pattern is formed by a laser removing selected amounts ofmaterial from the fabric. For lighter locations of the finishingpattern, a greater depth of the indigo ring-dyed cotton warp yarn isremoved relative darker locations of the finishing pattern where alesser depth of the indigo ring-dyed cotton warp yarn is removed.

The fabric includes yarns that are ring dyed, having an outer ring andan inner core. The outer ring is indigo colored due to being penetratedthrough by the indigo dye while the inner core is white or off-whitecolored due to not being penetrated to by the indigo dye. A crosssection of a ring-dyed yarn comprises a thickness of the outer ring thatis at least about 10 percent and less than about 12.5 percent of a totalthickness of the yarn.

For a first grayscale level, the laser removes a first depth of a crosssection of a first ring-dyed yarn, leaving a first thickness of thefirst ring-dyed yarn remaining in a direction from an outer side of thefabric to a bottom side of the fabric. For a second grayscale level, thelaser removes a second depth of a cross section of a second ring-dyedyarn, leaving a second thickness of the second ring-dyed yarn remainingin a direction from the outer surface of the fabric to the bottom of thefabric. The first grayscale level is a darker shade than the secondgrayscale level. The second depth is greater than the first depth. Thefirst thickness is thicker than the second thickness.

In various implementations, the finishing pattern can have at least 64different grayscale levels. The finishing pattern can have at least 128different grayscale levels. The finishing pattern can have at least 256different grayscale levels.

A thickness of the outer ring can be at least about 11 percent of atotal thickness of the yarn. A thickness of the outer ring can be atleast about 12 percent to about 12.5 percent of a total thickness of theyarn. It is undesirable for the outer ring to be too thin, or else thereis not enough indigo dyed material to work with.

In an implementation, an article of clothing includes: a fabriccomprising indigo ring-dyed yarn; and a finishing pattern on the fabric,where the finishing pattern is formed by a laser removing selectedamounts of material from the fabric. For lighter locations of thefinishing pattern, a greater depth of the indigo ring-dyed cotton warpyarn is removed, which is relative to darker locations of the finishingpattern where a lesser depth of the indigo ring-dyed cotton warp yarn isremoved.

The fabric has yarns that are ring dyed having an outer ring and aninner core. A cross section of a ring-dyed yarn has a thickness of theouter ring that is at least about 10 percent and less than about 15percent of a total thickness of the yarn.

In various implementations, a thickness of the outer ring can be lessthan about 14 percent of a total thickness of the yarn. A thickness ofthe outer ring can be less than about 13 percent of a total thickness ofthe yarn. A thickness of the outer ring is less than about 12 percent ofa total thickness of the yarn.

In an implementation, an article of clothing includes: a fabric madefrom indigo ring-dyed yarn; and a finishing pattern on the fabric, wherethe finishing pattern is formed by a laser removing selected amounts ofmaterial from the fabric. The fabric has yarns that are ring dyed havingan outer ring and an inner core. The outer ring is indigo colored due tobeing penetrated through by the indigo dye while the inner core is whiteor off-white colored due to not being penetrated to by the indigo dye. Across section of a ring-dyed yarn has a thickness of the outer ring thatis about 10 percent of a total thickness of the yarn.

In various implementations, cross sections of a plurality of ring-dyedyarns of the article of clothing can have outer ring thicknesses of 10percent of a total thickness of the yarn with a variation of plus orminus 5 percent. Cross sections of a plurality of ring-dyed yarns of thearticle of clothing can have outer ring thicknesses of 10 percent of atotal thickness of the yarn with a variation of plus or minus 10percent. Cross sections of a plurality of ring-dyed yarns of the articleof clothing can have outer ring thicknesses of 10 percent of a totalthickness of the yarn with a variation of plus or minus 15 percent.Cross sections of a plurality of ring-dyed yarns of the article ofclothing can have outer ring thicknesses of 10 percent of a totalthickness of the yarn with a variation of plus or minus 20 percent.Cross sections of a plurality of ring-dyed yarns of the article ofclothing can have outer ring thicknesses of 10 percent of a totalthickness of the yarn with a variation of plus or minus 25 percent.

Other objects, features, and advantages of the present invention willbecome apparent upon consideration of the following detailed descriptionand the accompanying drawings, in which like reference designationsrepresent like features throughout the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a process flow for manufacturing apparel such as jeanswhere garments are finished using a laser.

FIG. 2 shows a flow for fabric processing to produce a laser-sensitivefinished fabric.

FIG. 3 shows a flow for a dyeing process.

FIG. 4 shows technique of using a dye range to dye yarn.

FIG. 5 shows a weave pattern for a denim fabric.

FIG. 6 shows a cross section of a dyed yarn with a ring dyeing effect.

FIG. 7 shows a technique of laser finishing denim fabric made fromring-dyed yarn.

FIG. 8 shows a computer system which is part of a laser finishing systemfor apparel or system for manufacturing a fabric with enhanced responsecharacteristics for laser finishing.

FIG. 9 shows a system block diagram of the computer system.

FIGS. 10-13 show how the laser alters the color of ring-dyed yarn.

FIGS. 14-16 show the impact of the thickness or depth of the ring dye onthe laser's ability alter the color of the ring-dyed yarn.

FIGS. 17-18 show photomicrographs of cross sections of warp yarn, beforeand after lasering.

FIGS. 19 and 20 show for the same ring dye thickness or depth,percentages of exposed white fibers for a fine yarn and a coarse yarn,respectively.

FIGS. 21 and 22 show cross sections of a coarse yarn and a fine yarn,respectively, with elastane cores.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a process flow 101 for manufacturing apparel such as jeans,where garments are finished using a laser. The fabric or material forvarious apparel including jeans is made from natural or synthetic fibers106, or a combination of these. A fabric mill takes fibers and processes109 these fibers to produce a laser-sensitive finished fabric 112, whichhas enhanced response characteristics for laser finishing.

Some examples of natural fibers include cotton, flax, hemp, sisal, jute,kenaf, and coconut; fibers from animal sources include silk, wool,cashmere, and mohair. Some examples of synthetic fibers includepolyester, nylon, spandex or elastane, and other polymers. Some examplesof semisynthetic fibers include rayon, viscose, modal, and lyocell,which are made from a regenerated cellulose fiber. A fabric can be anatural fiber alone (e.g., cotton), a synthetic fiber alone (e.g.,polyester alone), a blend of natural and synthetic fibers (e.g., cottonand polyester blend, or cotton and spandax), or a blend of natural andsemisynthetic fibers, or any combination of these or other fibers.

For jeans, the fabric is typically a denim, which is a sturdy cottonwarp-faced textile in which a weft passes under two or more warpthreads. This twill weaving produces a diagonal ribbing. The yarns(e.g., warp yarns) are dyed using an indigo or blue dye, which ischaracteristic of blue jeans.

Although this patent describes the apparel processing and finishing withrespect to jeans, the invention is not limited jeans or denim products,such as shirts, shorts, jackets, vests, and skirts. The techniques andapproaches described are applicable to other apparel and products,including nondenim products and products made from knit materials. Someexamples include T-shirts, sweaters, coats, sweatshirts (e.g., hoodies),casual wear, athletic wear, outerwear, dresses, evening wear, sleepwear,loungewear, underwear, socks, bags, backpacks, uniforms, umbrellas,swimwear, bed sheets, scarves, and many others.

A manufacturer creates a design 115 (design I) of its product. Thedesign can be for a particular type of clothing or garment (e.g., men'sor women's jean, or jacket), sizing of the garment (e.g., small, medium,or large, or waist size and inseam length), or other design feature. Thedesign can be specified by a pattern or cut used to form pieces of thepattern. A fabric is selected and patterned and cut 118 based on thedesign. The pattern pieces are assembled together 121 into the garment,typically by sewing, but can be joined together using other techniques(e.g., rivets, buttons, zipper, hoop and loop, adhesives, or othertechniques and structures to join fabrics and materials together).

Some garments can be complete after assembly and ready for sale.However, other garments are unfinished 122 and have additional laserfinishing 124. The finishing may include tinting, washing, softening,and fixing. For distressed denim products, the finishing can includeusing a laser to produce a wear pattern according to a design 127(design II). Some additional details of laser finishing are described inU.S. patent application 62/377,447, filed Aug. 19, 2016, which isincorporated by reference. U.S. patent application Ser. Nos. 15/841,263,15/841,268, 15/841,271, and 15/841,272, filed Dec. 13, 2017; Ser. No.15/682,507, filed Aug. 21, 2017; and 62/433,746, filed Dec. 13, 2016,are also incorporated by reference.

Design 127 is for postassembly aspects of a garment while design 115 isfor preassembly aspects of a garment. After finishing, a finishedproduct 130 is complete and ready for sale. The finished product isinventoried and distributed 133, delivered to stores 136, and sold toconsumers or customers 139. The consumer can buy and wear worn bluejeans without having to wear out the jeans themselves, which usuallytakes significant time and effort.

Traditionally, to produce distressed denim products, finishingtechniques include dry abrasion, wet processing, oxidation, or othertechniques, or combinations of these, to accelerate wear of the materialin order to produce a desired wear pattern. Dry abrasion can includesandblasting or using sandpaper. For example, some portions or localizedareas of the fabric are sanded to abrade the fabric surface. Wetprocessing can include washing in water, washing with oxidizers (e.g.,bleach, peroxide, ozone, or potassium permanganate), spraying withoxidizers, washing with abrasives (e.g., pumice, stone, or grit).

These traditional finishing approaches take time, incur expense, andimpact the environment by utilizing resources and producing waste. It isdesirable to reduce water and chemical usage, which can includeeliminating the use agents such as potassium permanganate and pumice. Analternative to these traditional finishing approaches is laserfinishing.

FIG. 2 shows a flow for fabric processing 109 to produce alaser-sensitive finished fabric. In a specific implementation, thefabric is laser-sensitive denim that is made for laser finishing, wherethe laser produces a distressed finish.

Denim fabric is typically made from cotton, which is a plant-basedcellulose fiber. There are many different varieties of cotton includingupland cotton and long staple cotton, also know as Pima cotton. Uplandcotton has fiber lengths from about 13 to 35 millimeters, while longstaple cotton have fiber lengths from about 25 to 65 millimeters. Thefiber length for denim is generally about 28 millimeters or greater.Denim is often made from upland cotton, but may be from other varietiesor a blend of different varieties of cotton.

A cotton picker machine picks the cotton bolls from the cotton plant.The cotton bolls are the fruit of the cotton plant and include lint andcotton seeds. The cotton fibers twist and spiral together. A cotton ginseparates the lint from the cotton seeds and other debris, which arediscarded and used for other purposes (e.g., extracting cottonseed oil).Cotton is generally a white or off-white color. The cotton fiber ishollow, allowing the fiber to absorb moisture—making cotton warm in thewinter and cool in the summer.

Fiber 106 can be 100 percent cotton fiber. Or fiber 106 can be a blend,including cotton and other noncotton fibers to modify thecharacteristics of the fabric. For example, spandex, elastane, or otherelastic polyurethane fiber can be blended with the cotton fibers to givethe denim a stretch characteristic.

By spinning 211 the fiber, an undyed yarn 214 is obtained. Duringspinning, cotton staple fibers or a blend of cotton and other fibers aretwisted together to form a continuous spun yarn. Depending on thespecific spinning process, a diameter and number of twists in the yarncan vary. The undyed yarn is the same color as the cotton fiber, whiteor off white.

Spinning can be by, for example, ring spinning, rotor spinning, or otherspinning technique. Another spinning technique is core spinning, where afiber (e.g., staple fiber) is wound around a core of another material,such as polyester or elastane. Core spinning can be used to be usedcreate stretch denim material.

After spinning and before dyeing, the yarn can be mercerized 218 toobtain a mercerized yarn 223. Mercerization can also be performed afterweaving. When performed on the undyed yarn, the mercerization can bereferred to as premercerization. When performed on the fabric, themercerization can be referred to as fabric mercerization. Mercerizationis optional and yarns and fabrics are not necessarily mercerized. Ifused, mercerization is usually done only once in the process, eitheryarn premercerization or fabric mercerization.

Mercerization strengthens the yarn and gives the yarn a more lustrousappearance. Mercerization alters the chemical structure of the cottonfiber. Mercerizing results in the swelling of the cell wall of thecotton fiber. This causes an increase in the surface area andreflectance, and gives the fiber a softer feel. In an implementation,for premercerization, the yarn is treated in a sodium hydroxide bath (orother chemical, typically highly alkaline solution, that causes thefibers to swell). This is followed with an acid bath that neutralizesthe sodium hydroxide.

After spinning and optionally mercerization, a dyeing process 227 inwhich the yarn is dyed. For blue denim, the undyed yarn is dyed using anindigo dye to obtain a dyed yarn 230, which will be indigo blue. Thedyed yarn is woven 243 to obtain a woven fabric 246, which can befurther finished by fabric finishing 259. Fabric finishing may include,for example, preshrinking. This results in laser-sensitive finishedfabric 112.

FIG. 3 shows a flow for dyeing process 217 that includes dyeing usingindigo. Indigo dye is blue dye with a chemical formula C16H10N2O2.Indigo dye can be plant-based or synthetic. Indigo dye has very lowsolubility in water and is considered insoluble. To be dissolved, theindigo dye is converted into a soluble form by a reduction process. Achemical reduction process is to use, for example, sodium hydrosulphiteor other chemical constituent, which reduces indigo rapidly in solutionat temperatures from about 30 to 60 degrees Celsius. Other reductionprocesses include bacterial reduction and electrochemical reduction.

For dyeing, a pH of the reduced indigo solution can be a range fromabout 10.5 to about 13, which is a basic solution. In chemistry, pH is anumeric scale that specifies an acidity or basicity (or alkalinity) ofan aqueous solution in which 7 is considered neutral. Water has a pH of7. A pH value is defined as the decimal logarithm of the reciprocal ofthe hydrogen ion activity in a solution. Solutions having pH greaterthan 7 would be consider basic, while solutions with pH less than 7would be consider acidic. A usual range for pH is from 0 to 14, but thepH value can be below 0 or above 14. The pH is a relative value: Thehigher the pH indicates the greater the basicity or less the acidity ofa solution. The lower the pH indicates the less the basicity or greaterthe acidity of a solution.

An indigo dying process can include, optionally, a sulfur bottoming 306before dyeing with indigo. For sulfur bottoming, the yarn is first dyedusing a sulfur dye or sulfur dyestuff. Often the sulfur dye is black orgray, but can be other colors. Generally sulfur bottoming is used togive yarn a particular color cast. Sulfur bottoming is optional and canbe omitted from the dyeing process.

Indigo dyeing occurs by dipping 310 or immersing yarn into a vat withthe reduced indigo dye. The color of the reduced indigo dye solution isnot indigo or blue, but rather greenish or yellowish-green in color.When a white yarn is dipped into and removed from a vat with reducedindigo dye, the yarn will be yellowish-green in color. However, byexposure to oxygen in the air, the indigo oxidizes 315, and slowly overtime, the yellowish-green yarn will turn the familiar blue colorassociated indigo. The blue color is caused by chromophores trapped inthe fabric which reflect light as a blue color. The blue color of indigohas a wavelength between about 420 to 465 nanometers.

The dye dipping and oxidizing steps can be repeated multiple times 319,such as 2, 3, 4, 5, 6, 7, 8, 12, or more times. Multiple dips can beused to obtain deeper shades of blue. With each dip, the dye penetrates(e.g., migrates or diffuses) more toward a center or core of the yarn,rather than staying on the surface or close to the surface of the yarn.

After indigo dying is completed, the process can include, optionally, asulfur topping topping 324. Sulfur topping is similar to sulfurbottoming, but sulfur topping occurs after indigo dyeing instead ofbefore. Sulfur topping is optional and can be omitted from the dyeingprocess.

In an implementation, the dying process includes sulfur bottoming,indigo dyeing, and sulfur topping. In an implementation, the sulfurbottoming and sulfur topping are not used, and the yarn will be dyedusing only indigo. Another implementation includes sulfur bottoming andindigo dyeing, and not sulfur topping. Another implementation includesindigo dyeing and sulfur topping, and not sulfur bottoming.

It should be understood that the invention is not limited to thespecific flows and steps presented. A flow of the invention may haveadditional steps (not necessarily described in this patent), differentsteps which replace some of the steps presented, fewer steps or a subsetof the steps presented, or steps in a different order than presented, orany combination of these. Further, the steps in other implementations ofthe invention may not be exactly the same as the steps presented and maybe modified or altered as appropriate for a particular application orbased on the data or situation.

FIG. 4 shows technique of using an indigo dye range 408 to dye yarn. Adye range machine has that a number of boxes or vats, which are used tohold the solutions that the yarn will be dipped. Dye ranges can have anynumber of boxes, such as 6 boxes, 8 boxes, or 12 boxes, or greater. Withgreater number of boxes, more dips are possible.

The boxes or vats 412 for the dye range are typically housed on onefloor (e.g., first floor or basement) a building. The dye range has askyer mechanism 416 with extends through the ceiling of the floor withboxes into upper floors of the building, such as the second and thirdfloors, or higher floors. For example, for a three floor unit, whereeach floor is about 12 feet, the skyer unit can extend into the air atleast 24 feet.

During operation, undyed yarn 214 is conducted or transported viarollers, pulleys, and other mechanisms and pathways through the variousboxes (e.g., vat 1, vat 2, and vat 3) to dip the yarn into the solutionswithin the boxes. The solutions in the boxes can be for sulfur bottoming(optional), indigo dip in a reduced indigo solution, and sulfur topping(optional). Between dips, the yarn is conducted via the skyer above theboxes or vats (or urns or vessels), which exposes the yarn to oxygen soit can oxidize and the indigo can turn blue. At the end of the process,dyed yarn 220 is obtained.

FIG. 5 shows a weave pattern of a denim fabric 220. A loom does theweaving. In weaving, warp is the lengthwise or longitudinal yarn orthread in a roll, while weft or woof is the transverse thread. The weftyarn is drawn through the warp yarns to create the fabric. In FIG. 5,the warps extend in a first direction 505 (e.g., north an south) whilethe wefts extend in a direction 516 (e.g., east and west). The wefts areshown as a continuous yarn that zigzags across the wefts (e.g., carriedacross by a shuttle or a rapier of the loom). Alternatively, the weftscould be separate yarns. In some specific implementations, the warp yarnhas a different weight or thickness than the weft yarns. For example,warp yarns can be coarser than the weft yarns.

For denim, dyed yarn 220 is used for the warp, and undyed or white yarnis typically used for the weft yarn. In some denim fabrics, the weftyarn can be dyed and have a color other than white, such as red. In thedenim weave, the weft passes under two or more warp threads. FIG. 5shows a weave with the weft passing under two warp threads.Specifically, the fabric weave is known as a 2×1 right-hand twill. For aright-hand twill, a direction of the diagonal is from a lower left to anupper right. For a left-hand twill, a direction of the diagonal is froman lower right to an upper left. But in other denim weaves, the weft canpass under a different number of warp threads, such as 3, 4, 5, 6, 7, 8,or more. In other implementation, the denim is a 3×1 right-hand twill,which means the weft passes under three warp threads.

Because of the weave, one side of the fabric exposes more of the warpyarns (e.g., warp-faced side), while the other side exposes more of theweft yarns (e.g., weft-faced side). When the warp yarns are blue andweft yarns are white, a result of the weave is the warp-faced side willappear mostly blue while the reverse side, weft-faced side, will appearmostly white.

In denim, the warp is typically 100 percent cotton. But some warp yarnscan be a blend with, for example, elastane to allow for warp stretch.And some yarns for other fabrics may contain other fibers, such aspolyester or elastane as examples.

FIG. 6 shows a cross section of a dyed yarn with a ring dyeing effect. Aring dyeing effect occurs when dyeing of a yarn does not diffuse orpenetrate completely through the yarn. Rather, a surface layer 606 ofthe yarn is dyed, while a core 612 of the yarn is not. The core wouldremain undyed and, for example, white. In denim, the warp yarns areindigo dyed, and a cross section of ring-dyed warp yarns would besimilar to that shown in FIG. 6.

The yarn has a diameter 622, the ring dyed portion has a thickness 626,and the core has a diameter 629. An area of the yarn, A(yarn), isPi*(D622/2){circumflex over ( )}2, where Pi a mathematical constant, theratio of a circle's circumference to its diameter, approximated as3.14159, D622 is diameter 622, and {circumflex over ( )}2 indicates thequantity in parenthesis to the power 2 or squared. An area of the core,A(core), is Pi*(D612/2){circumflex over ( )}2, where D612 is diameter612. The area of the ring dyed portion is A(yarn) minus A(core).

To simplify the diagram, FIG. 6 shows a solid or hard boundary betweenthe dyed portion and the undyed core portion. In practice, the boundarybetween the dyed and undyed portions can be due to dye diffusion, agradient, where the dye gradually lightens or fades in blue color.

Ring dyeing is often considered undesirable since the dye is not evenlybeen distributed through the yarn. However, for laser finishing,ring-dyed yarn can improve a fabric's response characteristics to thelaser. Fabric with ring-dyed yarn has an improved grayscale resolution,allowing the laser to obtain a greater number of gray levels that arevisually distinguishable from each other.

FIG. 7 shows a technique of laser finishing denim fabric 703 withring-dyed yarn 708. In denim, the ring-dyed yarn is the warp yarn. Thefabric or garment is positioned in front of a laser 712 that emits alaser beam 717 that strikes the fabric. A computer 721 controls a powerlevel and exposure time of the laser. The resulting laser beam removesat least a portion of the dyed yarn with chromophores from the fabric.Depending on the amount of dyed yarn with chromophores removed, theshade of blue of the fabric can be altered or varied, from deep blue towhite.

The computer can control a positioning mechanism 726 to position thelaser to print, for example, a distressing pattern or any other patternonto the garment. For example, the laser can print the pattern row byrow (or column by column). Also, the laser can make multiple passesacross one or more rows (or columns). Multiple passes can be used tofurther increase or enhance grayscale resolution. Also laser passes maybe made between rows (e.g., half or quarter rows), which can increasepixel resolution.

Laser finishing is a technique that includes the use of a laser. A laseris a device that emits light through a process of optical amplificationbased on the stimulated emission of electromagnetic radiation. Lasersare used for bar code scanning, medical procedures such as correctiveeye surgery, and industrial applications such as welding. A particulartype of laser for finishing apparel is a carbon dioxide laser, whichemits a beam of infrared radiation.

The laser can be controlled by an input file and control software toemit a laser beam onto fabric at a particular position or location at aspecific power level for a specific amount of time. Further, the powerof the laser beam can be varied according to a waveform such as a pulsewave with a particular frequency, period, pulse width, or othercharacteristic. Some aspects of the laser that can be controlled includethe duty cycle, frequency, marking or burning speed, and otherparameters.

The duty cycle is a percentage of laser emission time. Some examples ofduty cycle percentages include 40, 45, 50, 55, 60, 80, and 100 percent.The frequency is the laser pulse frequency. A low frequency might be,for example, 5 kilohertz, while a high frequency might be, for example,25 kilohertz. Generally, lower frequencies will have higher surfacepenetration than high frequencies, which has less surface penetration.

The laser acts like a printer and “prints,” “marks,” or “burns” a wearpattern (specified by, for example, an input file) onto the garment. Thefabric that is exposed to the infrared beam changes color, lighteningthe fabric at a specified position by a certain amount based on thelaser power, time of exposure, and waveform used. The laser continuesfrom position to position until the wear pattern is completely printedon the garment.

In a specific implementation, the laser has a resolution of about 34dots per inch (dpi), which on the garment is about 0.7 millimeters perpixel. The technique described in this patent is not dependent on thelaser's resolution, and will work with lasers that have more or lessresolution than 34 dots per inch. For example, the laser can have aresolution of 10, 15, 20, 25, 30, 40, 50, 60, 72, 80, 96, 100, 120, 150,200, 300, or 600 dots per inch, or more or less than any of these orother values. Typically, the greater the resolution, the finer thefeatures that can be printed on the garment in a single pass. By usingmultiple passes (e.g., 2, 3, 4, 5, or more passes) with the laser, theeffective resolution can be increased. In an implementation, multiplelaser passes are used.

A system of laser finishing can include a computer to control or monitoroperation, or both. FIG. 8 shows an example of a computer that iscomponent of a laser finishing system. The computer may be a separateunit that is connected to a laser system, or may be embedded inelectronics of the laser system. In an embodiment, the inventionincludes software that executes on a computer workstation system, suchas shown in FIG. 8.

Further, a system for manufacturing a fabric with enhanced responsecharacteristics for laser finishing can also include a computer tocontrol or monitor operation, or both. FIG. 8 also shows an example of acomputer that is component of a fabric manufacturing system. Forexample, the computer can be connected to control the spinning machines,dye range or dyeing machines, loom or weaving machines, or othermachines used in the manufacture or processing of the fabric, or acombination of these.

FIG. 8 shows a computer system 801 that includes a monitor 803, screen805, enclosure 807, keyboard 809, and mouse 811. Mouse 811 may have oneor more buttons such as mouse buttons 813. Enclosure 807 (may also bereferred to as a system unit, cabinet, or case) houses familiar computercomponents, some of which are not shown, such as a processor, memory,mass storage devices 817, and the like.

Mass storage devices 817 may include mass disk drives, floppy disks,magnetic disks, optical disks, magneto-optical disks, fixed disks, harddisks, CD-ROMs, recordable CDs, DVDs, recordable DVDs (e.g., DVD-R,DVD+R, DVD-RW, DVD+RW, HD-DVD, or Blu-ray Disc), flash and othernonvolatile solid-state storage (e.g., USB flash drive or solid statedrive (SSD)), battery-backed-up volatile memory, tape storage, reader,and other similar media, and combinations of these.

A computer-implemented or computer-executable version or computerprogram product of the invention may be embodied using, stored on, orassociated with computer-readable medium. A computer-readable medium mayinclude any medium that participates in providing instructions to one ormore processors for execution. Such a medium may take many formsincluding, but not limited to, nonvolatile, volatile, and transmissionmedia. Nonvolatile media includes, for example, flash memory, or opticalor magnetic disks. Volatile media includes static or dynamic memory,such as cache memory or RAM. Transmission media includes coaxial cables,copper wire, fiber optic lines, and wires arranged in a bus.Transmission media can also take the form of electromagnetic, radiofrequency, acoustic, or light waves, such as those generated duringradio wave and infrared data communications.

For example, a binary, machine-executable version, of the software ofthe present invention may be stored or reside in RAM or cache memory, oron mass storage device 817. The source code of the software of thepresent invention may also be stored or reside on mass storage device817 (e.g., hard disk, magnetic disk, tape, or CD-ROM). As a furtherexample, code of the invention may be transmitted via wires, radiowaves, or through a network such as the Internet.

FIG. 9 shows a system block diagram of computer system 801 used toexecute software of the present invention. As in FIG. 8, computer system801 includes monitor 803, keyboard 809, and mass storage devices 817.Computer system 801 further includes subsystems such as centralprocessor 902, system memory 904, input/output (I/O) controller 906,display adapter 908, serial or universal serial bus (USB) port 912,network interface 918, and speaker 920. The invention may also be usedwith computer systems with additional or fewer subsystems. For example,a computer system could include more than one processor 902 (i.e., amultiprocessor system) or the system may include a cache memory.

The processor may be a dual core or multicore processor, where there aremultiple processor cores on a single integrated circuit. The system mayalso be part of a distributed computing environment. In a distributedcomputing environment, individual computing systems are connected to anetwork and are available to lend computing resources to another systemin the network as needed. The network may be an internal Ethernetnetwork, Internet, or other network.

Arrows such as 922 represent the system bus architecture of computersystem 801. However, these arrows are illustrative of anyinterconnection scheme serving to link the subsystems. For example,speaker 920 could be connected to the other subsystems through a port orhave an internal connection to central processor 902. Computer system801 shown in FIG. 8 is but an example of a computer system suitable foruse with the present invention. Other configurations of subsystemssuitable for use with the present invention will be readily apparent toone of ordinary skill in the art.

Computer software products may be written in any of various suitableprogramming languages, such as C, C++, C#, Pascal, Fortran, Perl,Matlab, SAS, SPSS, JavaScript, AJAX, Java, Python, Erlang, and Ruby onRails. The computer software product may be an independent applicationwith data input and data display modules. Alternatively, the computersoftware products may be classes that may be instantiated as distributedobjects. The computer software products may also be component softwaresuch as Java Beans (from Oracle Corporation) or Enterprise Java Beans(EJB from Oracle Corporation).

An operating system for the system may be one of the Microsoft Windows®family of operating systems (e.g., Windows 95, 98, Me, Windows NT,Windows 2000, Windows XP, Windows XP x64 Edition, Windows Vista, Windows7, Windows 8, Windows 10, Windows CE, Windows Mobile, Windows RT),Symbian OS, Tizen, Linux, HP-UX, UNIX, Sun OS, Solaris, Mac OS X, AppleiOS, Android, Alpha OS, AIX, IRIX32, or IRIX64. Other operating systemsmay be used. Microsoft Windows is a trademark of Microsoft Corporation.Other operating systems may be used. A computer in a distributedcomputing environment may use a different operating system from othercomputers.

Any trademarks or service marks used in this patent are property oftheir respective owner. Any company, product, or service names in thispatent are for identification purposes only. Use of these names, logos,and brands does not imply endorsement.

Furthermore, the computer may be connected to a network and mayinterface to other computers using this network. For example, eachcomputer in the network may perform part of the task of the many seriesof steps of the invention in parallel. Furthermore, the network may bean intranet, internet, or the Internet, among others. The network may bea wired network (e.g., using copper), telephone network, packet network,an optical network (e.g., using optical fiber), or a wireless network,or any combination of these. For example, data and other information maybe passed between the computer and components (or steps) of a system ofthe invention using a wireless network using a protocol such as Wi-Fi(IEEE standards 802.11, 802.11a, 802.11b, 802.11e, 802.11g, 802.11i,802.11n, 802.11ac, and 802.11ad, just to name a few examples), nearfield communication (NFC), radio-frequency identification (RFID), mobileor cellular wireless (e.g., 2G, 3G, 4G, 3GPP LTE, WiMAX, LTE, LTEAdvanced, Flash-OFDM, HIPERMAN, iBurst, EDGE Evolution, UMTS, UMTS-TDD,1xRDD, and EV-DO). For example, signals from a computer may betransferred, at least in part, wirelessly to components or othercomputers.

FIGS. 10-13 show how the laser alters the color of ring-dyed yarn. FIG.10 shows a laser beam 1007 striking a ring-dyed yarn 1013 havingindigo-dyed fibers 1018 and white core fibers 1022. The laser removesthe dyed fibers, which can be by vaporizing or otherwise destroying thecotton fiber via heat or high temperature that the laser beam causes.

FIG. 11 shows the laser using a first power level setting or firstexposure time setting, or a combination of these, to remove some of thedyed fibers, but not revealing any of the white core fibers. The undyedfibers remain covered. There is no color change.

FIG. 12 shows the laser using a second power level setting or secondexposure time setting, or a combination of these, to remove more of thedyed fibers than in FIG. 11. The second power level is greater than thefirst power level, or the second exposure time setting is greater thanthe first exposure time setting, or a combination of these. The resultis some of the undyed fibers are revealed. There is a color change,subtle highlighting.

FIG. 13 shows the laser using a third power level setting or thirdexposure time setting, or a combination of these, to remove even more ofthe dyed fibers than in FIG. 12. The third power level is greater thanthe second power level, or the third exposure time setting is greaterthan the second exposure time setting, or a combination of these. Theresult is more of the undyed fibers are revealed. There is a colorchange, brighter highlighting.

Further, the diameter of lasers beam can be adjusted or changed. Thefocal distance between the lens and the fabric may also be adjusted tokeep the laser focused. In a specific laser finishing system, the laseris set to allow it to reach a size of an entire pair of pants from top(e.g., waistband) to bottom (e.g., leg opening ends); at that focaldistance, the resolution for the laser is 1 millimeter. The resolutioncan be increased, but then the laser will need to be moved closer to thefabric, and the laser would not reach a typical pair of pants, top tobottom.

The laser system has a scan speed, which is also known as a pixel timeor exposure time setting. This is the amount of time the laser spends ateach pixel. As an example, a black pixel (which prints as “white” on thedenim) of “0” is 100 percent of the pixel time, and each fading grey isa percentage of that pixel time. So a very light file (e.g., lesshighlighting) will move more quickly across a garment than a moreintense one. When using an enhanced laser-sensitive fabric, less timeand energy is needed to create the pattern. In an implementation, whenthe laser power level or intensity is fixed, the exposure time is usedto determine the energy a pixel of the apparel is exposed to.

In another implementation, the exposure time is fixed, and the laserpower level or intensity is adjustable or variable to determine theenergy at a pixel of the apparel is exposed to. In anotherimplementation, the laser power level and exposure time are bothvariable to determine the energy at a pixel of the apparel is exposedto.

FIGS. 14-16 show the impact of the thickness or depth of the ring dye onthe laser's ability alter the color of the ring-dyed yarn. FIG. 14 showsa first thickness or depth of the ring dye. FIG. 15 shows a secondthickness or depth of the ring dye. FIG. 16 shows a third thickness ordepth of the ring dye. The first thickness is thicker than the secondthickness, and the second thickness is greater than the first thickness.

FIG. 14 shows that due to the first thickness being relatively thick,the laser does not remove sufficient amount of the dyed region to exposethe core fibers. There is no color change, and the result is nohighlighting.

FIG. 15 shows that due to the second thickness being a medium thickness,the laser removes some of the dyed region so that some of the white corefibers are exposed. The result is slight highlighting.

FIG. 16 shows that due to the third thickness being a relatively narrowthickness, the laser removes the dyed region so that many of the whitecore fibers are exposed. The result is very bright highlighting.

FIG. 17 shows a photomicrograph of a cross section of warp yarn from adenim fabric, before lasering. The warp yarns exhibit ring dying.

FIG. 18 shows a photomicrograph of a cross section of warp yarn from adenim fabric, after lasering. Some of the ring dyed portion has beenremoved by the laser, and the white fibers of the core are exposed. Thedyed portion (e.g., indigo- or blue-colored portion) can be referred toas an outer ring, while the undyed or less dyed portion (e.g., white oroff-white colored portion) can be referred to as an inner core.

If FIG. 18, some of the measured ring dye thicknesses are 91, 108, and92 microns. A measure distance of yarn surface to exposed fiber lengthis about 406 microns. A measured distance from yarn surface to exposedfiber length is about 406 microns. A measured distance from core edge toexposed fiber length is about 289 microns.

In a specific implementation of ring dyed yarn, the ring dye thicknessor depth penetrates no more than about 10 percent of the yarn thickness,from all surfaces (or sides). So, about 20 percent of the total diameteris dyed, and the core is 80 percent of the diameter.

Further, due to process variations, the total ring dye thickness(including both sides) can vary, such as 20 percent plus or minus 10,15, 20, 25, or even up to 50 percent in some instances. So, the rangescan be from about 18 to 22 percent, about 17 to 23 percent, about 16 to24 percent, about 15 to 25 percent, or up to about 10 to 30 percent. Thering dye thickness for a single side would about half of these values.More specifically, the range for a single-side ring dye thickness wouldbe about 9 to 11 percent, about 8.5 to 11.5 percent, about 8 to 12percent, about 7.5 to 12.5 percent, or up to about 5 to 15 percent.

As an example, in an implementation, for greater highlights from laserfinishing, the total ring-depth depth (which includes thicknesses ofboth sides of the outer ring) should be from about 15 percent to about25 percent of the yarn thickness or diameter. When less than 15 percent,the ring dye can wash down too fast, and there not enough coloredmaterial for the laser to work with. With more than 25 percent ring-dyeis not responsive to provide as large a number of grayscale levels(e.g., not able to provide 64 or more different levels, 128 or moredifferent levels, or 256 or more different levels). Therefore, for asingle side, the outer ring thickness can be from about 7.5 percent(e.g., 15 percent divided by 2) to about 12.5 percent (e.g., 25 percentdivided by 2).

As a result of the process of making a fabric, a fabric has responsecharacteristics for laser finishing. It is desirable that the fabrichave the following good or strong performance characteristics including:(i) fast or relatively fast color change with minimal laser irradiation,(ii) color changes to a hue close to white (e.g., 64 or more grayscalelevels, 128 grayscale levels, or 256 or more grayscale levels), and(iii) minimal degradation to strength or stretch properties, or anycombination of these. It is undesirable that the fabric have thefollowing poor performance characteristics such as: (i) slow colorchange, (ii) color changes to a color with noticeable hue, such as grey,blue, or green, instead of white or (iii) unacceptable degradation tostrength or stretch properties, or any combination of these.

A fabric with good characteristics for laser finishing has yarns withundyed core fibers (white fibers) closer to their surfaces. A process isto manufacture yarns and this fabric can include one or more of thefollowing techniques, in any combination:

1. Lower pH. Lowering the pH reduces indigo dye affinity to the yarnfiber, reducing penetration. In a specific implementation, the pH of theindigo dye solutions used in the dyeing process are about 11.6 or less,11.5 or less, 11.4 or less, 11.3 or less, 11.2 or less, or 11.1 or less.In an implementation, the pH will be in a range from about 10.7 to 11.2.By maintaining pH at these levels, the dye yarn will exhibit the ringdye effect.

2. Premercerization. Swelling of fibers makes indigo dye penetrationmore difficult, reducing ring-dye depth. When the yarns have beenpremercerization, the pH can be increased slightly and the yarn willstill have a desired ring dye. For example, with premercerization, thepH of the indigo dye solution can be increased to 11.2, rather thanusing 10.7 or 10.8.

3. Lower dye concentration, faster dying speed, number of dips, lowertemperatures, or any combination of these. If shade matching is notimportant, a technique reduces opportunity for dye penetration. Forexample, the dye concentration can be in a range from, for example,about 1.0 to 1.05 grams per liter. In other implementations, the rangecan extend up to 3 grams per liter.

For dips, there can be, for example, about 8 dye dips. In otherimplementations, there can be 8 or fewer dye dips, such as 2, 3, 4, 5,6, or 7. In other implementations, there can be more than 8 dye dips,such as 9, 10, 11, 12, or more than 12 dye dips. With more dips, a lowerdye concentration (or adjustment in other parameter) can be used toobtain the same shading and core diameter. With fewer dips, a higher dyeconcentration (or adjustment in other parameter) can be used to obtainthe same shading and core diameter.

Alternatively, or in combination with lower dye concentration, there canbe faster speed indigo dips in the indigo, or reduce time of yarn inindigo dips. The machine speed of the dye range can be, for example,about 25 meters per minute. The machine speed of the dye range canexceed 25 meters per minute, which will decrease the dye dip time. Inother implementations, the machine speed can be less than 25 meters perminute, and other parameters such as the dye concentration can be usedto obtain the same shading and core diameter.

Lower temperatures reduce diffusion rate, and thus the ring dye effectwill be enhanced and more controllable at lower temperatures. The vatsor dye boxes typically have a temperature controller to control heatingof the indigo solution. A temperature of the indigo solution istypically room temperature (e.g., 20 degrees Celsius) or above. In animplementation, the temperature range of the indigo solution is fromabout 20 degrees Celsius to about 30 degrees Celsius. For example, thetemperature can be 30 degrees Celsius or below. In an implementation,the temperature range of the indigo solution is from about 30 degreesCelsius to about 40 degrees Celsius. For example, the temperature can be40 degrees Celsius or below. In an implementation, the temperature rangeof the indigo solution is from about 40 degrees Celsius to about 50degrees Celsius. For example, the temperature can be 50 degrees Celsiusor below. In an implementation, the temperature range of the indigosolution is from about 50 degrees Celsius to about 60 degrees Celsius.For example, the temperature can be 60 degrees Celsius or below. In animplementation, the temperature range of the indigo solution is fromabout 60 degrees Celsius to about 70 degrees Celsius. For example, thetemperature can be 70 degrees Celsius or below. Various otherparameters, such as dye concentration or number of dips, can be adjustedto compensate for higher or lower temperatures.

4. Higher yarn twist. High yarn twist makes dye penetration moredifficult, reducing ring-dye depth. For example, yarns for denim aretwisted in a range between 4.2 and 4.8 twists per inch or TPI. TPIrefers to the number of twist spirals in an inch of yarn. Generally,anything 4.6 or above would be considered a higher twist yarn. For someshrink-to-fit products, yarn twist can be about 4.8 twists per inch.

5. Coarse yarn count. Ring-dye depth is a lower percentage of the totalyarn diameter, leaving a large undyed yarn core. More fibers remain forimproved tear or tensile properties. For equivalent bath concentrationsand warp ends, ratio of dye to fiber mass in bath is lower. Fine yarnsare at risk of becoming dyed to the center, leaving no undyed fibers toprovide color change and highlight.

For fine yarns, dye penetration makes up a larger percentage of totalyarn diameter, leaving only a small white core, meaning the ratio ofblue to white fibers is higher. This causes the highlight to appearbluish rather than white. Fine yarns are also more at risk for physicalfailure before highlight is achieved due to removal of a largerpercentage of total fiber.

FIGS. 19 and 20 show for the same ring dye thickness or depth,percentages of exposed white fibers for a fine yarn and a coarse yarn,respectively. In FIG. 19, the fine yarn has, as an example, 28 percentof exposed white fibers. In FIG. 20, the coarse yarn has, as an example,50 percent of exposed white fibers.

6. Reduce, minimize, or eliminate sulfur bottoming. Due to the affinityof sulfur dyestuff to cotton, sulfur dyes penetrate to the yarn core,dyeing the once-white core fibers. The fabric will now highlight to thecolor of the sulfur bottom. A small amount of sulfur may be acceptableif the core fibers are dyed to a negligible color change. If sulfurbottoming is desired, a dark indigo dye can create the illusion ofbright highlights via contrast against base shade.

7. Sulfur topping. Sulfur topping is less risky than bottoming becausemany dye-sites are already occupied by indigo, and loose indigo slowspenetration of sulfur into yarn. However, sulfur topping stillcontributes to the total dye quantity; high concentrations can stilllead to poor performance, particularly with fine yarns.

8. Reduce or minimize elastane fibers in warp. Some warp-stretch fabricsmay show poor performance because the elastane core is clear rather thanwhite. This would mean the “target” for a white highlight is doughnutshaped yarn core, which is a more difficult target to hit, particularlyin finer yarn counts. Stronger performing warp-stretch fabrics shouldhave both a shallow ring-dye and a large yarn diameter.

Some warp-stretch failures may pertain to the translucent nature of theelastane core. Since the elastane core is translucent rather than opaquewhite, indigo dyed fibers are visible through the yarn core. FIGS. 21and 22 show cross sections of a coarse yarn and a fine yarn,respectively, with elastane cores.

In an implementation, a fabric with excellent performance characteristichas (i) no overdyes, no coatings, (ii) pure indigo dyed at the lowestpossible pH (indigo solution has pH of 11.2 or less), and (iii)premercerized warp yarns.

Some other important factors, having secondary impact, include: (i)coarse warp yarns (e.g., 7s-8s Ne rather than 13s-14s Ne), (ii) hightwist warp yarns (above 4.6 twists), (iii) dyed at highest speedallowable to achieve desired shade (can vary between suppliers based onmachinery), (iv) no sulfur bottoming or topping, and (v) 100 percentcotton warp.

Typically for denim, yarn counts range from a 7s Ne to a 16s Ne, thoughit is not uncommon to see counts as coarse as a 5s or as fine as a 20s.“Ne” represents an English cotton yarn count system (used by the textileindustry for cotton spun yarns). It is an indirect way of indicating thecoarseness of the yarn, where the lower the number, the coarser theyarn, lower number is a coarser yarn.

The English cotton yarn count system is calculated as follows: “Ne”refers to the number of hanks in pounds. One hank is equal to 840 yardsof yarn. For example, 7s Ne (or a 7s count) is equal to 7 times 840yards of yarn in 1 pound. And, 16s Ne (or a 16s count) is equal to 16times 840 yards of yarn in 1 pound.

Some denim yarns have slub, which means a yarn has been engineered withthick and thin places to create a particular aesthetic. The diameter ofthe yarn is not uniform and can vary across its length. Slub patternsaverage about 0.25 mile in length of repeat and vary from mill to mill.Thus, the Ne calculation gives the average fineness or thickness of ayarn. Generally, a yarn is described by its yarn count, spinning method,and twist multiple. As an example, men's denim fabric generally usecoarser counts like 7s and 8s, and women's denim fabrics generally usefiner counts of 10s, 12s, and 14s. For stretch products, some finercounts are used.

Although this patent specifically describes laser finishing of wovenfabrics, the techniques would also apply to knit fabrics used for knitapparel. A knit fabric is made by a series of interlocking loops ofyarn. For laser finishing of knits, the techniques described to produceor obtain a ring-dyed yarn apply. Ring-dyed yarn is used to produce theknit. The knit which is made from ring-dyed can be laser finished.

In an implementation, a method includes processing a cotton yarn usingan indigo dye to have a cross section having an outer ring and an innercore, where a thickness of the outer ring is about, for example, fromabout 7.5 percent to about 12.5 percent of a total thickness of theyarn, and the outer ring is indigo colored due to being penetratedthrough by the indigo dye while the inner core is white or off-whitecolored due to not being penetrated to by the indigo dye; and weavingthe dyed cotton yarn into a denim fabric, where the warp yarns includedyed cotton and the weft yarns include undyed cotton, and the denimfabric is to be finished by exposing the dyed cotton yarn to a laser.

When exposed to the laser, the laser creates a finishing pattern on asurface of the garment based on a laser input file provided to thelaser. The laser input file includes a laser exposure values fordifferent laser pixel location. For each laser exposure value, the laserremoves a depth or thickness of material from the surface of the denimmaterial that corresponds to the laser exposure value.

For lighter pixel locations of the finishing pattern, a greater depth ofthe indigo ring-dyed cotton yarn is removed, revealing a greater widthof an inner core of the dyed yarn, as compared to darker pixel locationsof the finishing pattern, where a lesser depth of the indigo ring-dyedcotton yarn is removed, revealing a lesser width of an inner core of thedyed yarn.

The laser file includes grayscale values for each pixel location to belasered. For example, a value can be from 0 to 255 (e.g., an 8-bitbinary value) for up to 256 levels of gray. In an implementation, thelower the value, the greater the thickness of the material that will beremoved. For a value 255, no material may be removed, while for 0, amaximum amount of material is removed to achieve a very white color,which would represent a well worn point (or pixel) in the finishingpattern. The 0 value may represent a removal of, for example, 50 percent(or more or less) of the thickness of the yarn.

In other implementations, reverse or negative logic may be use, wherethe greater the value, the less the thickness of the material that willbe removed. For example, the greater the value, the greater thethickness of the material that will be removed. For a value 0, nomaterial may be removed, while for 255, a maximum amount of material isremoved to achieve a very white color, which would represent a well wornpoint (or pixel) in the finishing pattern. The 255 value may represent aremoval of 50 percent (or more or less) of the thickness of the yarn.

In various implementations, the processing a cotton yarn can includeimmersing the cotton yarn into at least one indigo dye solution having apH in a range from about 10.7 to about 11.6. The processing a cottonyarn can include immersing the cotton yarn into at least one indigo dyesolution having a pH of about 11.6 or less.

The processing a cotton yarn can include immersing the cotton yarn intoat least one indigo dye solution having a pH in a range from about 10.7to about 11.2, and maintaining a temperature of the indigo dye solutionat about 50 degrees Celsius or less (e.g., or 60 degrees Celsius or lessor 70 degrees Celsius) while the cotton yarn is being immersed.

The processing a cotton yarn can include mercerizing an undyed cottonyarn in an alkaline solution before an initial immersion of the undyedyarn into an indigo dye solution. This may be referred to aspremercerizing the yarn.

The processing a cotton yarn can include not immersing the cotton yarninto a solution including sulfur dyestuff before an initial immersion ofthe cotton yarn into an indigo dye solution. This may be referred to asnot using sulfur bottoming during the processing.

The laser finishing can produce at least 64 different grayscale levels(e.g., at least 128 or at least 256) on the denim fabric. These would beoptically distinguishable (e.g., optically distinguishable by a camera,photospectrometer, or the like) grayscale levels on the denim fabric.This allows the finish pattern to show better highlights or a greaterdistinction between the highs and lows in the pattern. This facilitatesgarment laser patterning with better aesthetics instead of a duller,less attractive finish.

Further, based on a value stored in laser input file, the laser removesa selected depth of material starting from the outer surface of theyarn. And as a result, a vertical segment of the inner core is revealedby the laser between outer core segments (e.g., left and right outerring thickness) that is in a range from 0 to about 85 percent of thetotal thickness of the yarn. This produces at least 64 differentgrayscale levels (e.g., at least 128 or at least 256) on the denimmaterial.

The cotton yarn can have from about 4.2 to about 4.8 twists per inch.The processing a cotton yarn can include: mercerizing an undyed cottonyarn in an alkaline solution before an initial immersion of the undyedyarn into an indigo dye solution, and immersing the mercerized cottonyarn into five or fewer separate dips of indigo dye solution having a pHof about 11.6 or less.

This description of the invention has been presented for the purposes ofillustration and description. It is not intended to be exhaustive or tolimit the invention to the precise form described, and manymodifications and variations are possible in light of the teachingabove. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical applications.This description will enable others skilled in the art to best utilizeand practice the invention in various embodiments and with variousmodifications as are suited to a particular use. The scope of theinvention is defined by the following claims.

The invention claimed is:
 1. An article of clothing comprising: a fabriccomprising indigo ring-dyed yarn, wherein the fabric comprises yarnsthat are ring dyed comprising an outer ring and an inner core, the outerring is indigo colored due to being penetrated through by the indigo dyewhile the inner core is white or off-white colored due to not beingpenetrated to by the indigo dye; and a finishing pattern on the fabric,wherein the finishing pattern is formed by a laser removing selectedamounts of material from the fabric, before lasering, a cross section ofa ring-dyed yarn comprises a generally round shape with dyed indigofibers in the outer ring that surround the inner core, after beingexposed to the laser and the depth of material that has been removed, across section of the warp yarn comprises a region with a flattened shaperelative to the generally round shape before lasering, for lighterlocations of the finishing pattern, a greater depth of the indigoring-dyed yarn is removed, revealing a greater width of an inner core ofthe dyed yarn, as compared to darker locations of the finishing patternwhere a lesser depth of the indigo ring-dyed yarn is removed, revealinga lesser width of an inner core of the dyed yarn, and a cross section ofa ring-dyed yarn comprises a total ring dye thickness of the outer ringthat is at least 23 percent and less than 25 percent of a totalthickness of the yarn.
 2. The article of claim 1 wherein for a firstgrayscale level, the laser removes a first depth of a cross section of afirst ring-dyed yarn, leaving a first thickness of the first ring-dyedyarn remaining in a direction from an outer side of the fabric to abottom side of the fabric, for a second grayscale level, the laserremoves a second depth of a cross section of a second ring-dyed yarn,leaving a second thickness of the second ring-dyed yarn remaining in adirection from the outer surface of the fabric to the bottom of thefabric, the first grayscale level is a darker shade than the secondgrayscale level, the second depth is greater than the first depth, andthe first thickness is thicker than the second thickness.
 3. The articleof claim 1 wherein the finishing pattern comprises at least 64different, optically distinguishable grayscale levels.
 4. The article ofclaim 1 wherein the finishing pattern comprises at least 128 differentgrayscale levels.
 5. The article of claim 1 wherein the finishingpattern comprises at least 256 different, optically distinguishablegrayscale levels.
 6. An article of clothing comprising: a fabriccomprising indigo ring-dyed yarn, wherein the fabric comprises yarnsthat are ring dyed comprising an outer ring and an inner core, the outerring is indigo colored due to being penetrated through by the indigo dyewhile the inner core is white or off-white colored due to not beingpenetrated to by the indigo dye; and a finishing pattern on the fabric,wherein the finishing pattern is formed by a laser removing selectedamounts of material from the fabric, before lasering, a cross section ofa ring-dyed yarn comprises a generally round shape with dyed indigofibers in the outer ring that surround the inner core, after beingexposed to the laser and the depth of material that has been removed, across section of the warp yarn comprises a region with a flattened shaperelative to the generally round shape before lasering, for lighterlocations of the finishing pattern, a greater depth of the indigoring-dyed yarn is removed, revealing a greater width of an inner core ofthe dyed yarn, relative to darker locations of the finishing patternwhere a lesser depth of the indigo ring-dyed yarn is removed, revealinga lesser width of an inner core of the dyed yarn, and a cross section ofa ring-dyed yarn comprises a total ring dye thickness of the outer ringthat is at least 23 percent and less than 30 percent of a totalthickness of the yarn.
 7. The article of claim 6 wherein for a firstgrayscale level, the laser removes a first depth of a cross section of afirst ring-dyed yarn, leaving a first thickness of the first ring-dyedyarn remaining in a direction from an outer side of the fabric to abottom side of the fabric, for a second grayscale level, the laserremoves a second depth of a cross section of a second ring-dyed yarn,leaving a second thickness of the second ring-dyed yarn remaining in adirection from the outer surface of the fabric to the bottom of thefabric, the first grayscale level is a darker shade than the secondgrayscale level, the second depth is greater than the first depth, andthe first thickness is thicker than the second thickness.
 8. The articleof claim 6 wherein a total ring dye thickness of the outer ring is lessthan 28 percent of a total thickness of the yarn.
 9. The article ofclaim 6 wherein a total ring dye thickness of the outer ring is lessthan 26 percent of a total thickness of the yarn.
 10. The article ofclaim 6 wherein a total ring dye thickness of the outer ring is lessthan 24 percent of a total thickness of the yarn.
 11. An article ofclothing comprising: a fabric comprising indigo ring-dyed yarn, whereinthe fabric comprises yarns that are ring dyed comprising an outer ringand an inner core, the outer ring is indigo colored due to beingpenetrated through by the indigo dye while the inner core is white oroff-white colored due to not being penetrated to by the indigo dye; anda finishing pattern on the fabric, wherein the finishing pattern isformed by a laser removing selected amounts of material from the fabric,before lasering, a cross section of a ring-dyed yarn comprises agenerally round shape with dyed indigo fibers in the outer ring thatsurround the inner core, after being exposed to the laser and the depthof material that has been removed, a cross section of the yarn comprisesa region with a flattened shape relative to the generally round shapebefore lasering, for lighter locations of the finishing pattern, agreater depth of the indigo ring-dyed yarn is removed, revealing agreater width of an inner core of the dyed yarn, relative to darkerlocations of the finishing pattern where a lesser depth of the indigoring-dyed yarn is removed, revealing a lesser width of an inner core ofthe dyed yarn, and a cross section of a ring-dyed yarn comprises a totalring dye thickness of the outer ring that is 23 percent of a totalthickness of the yarn.
 12. The article of claim 11 wherein for a firstgrayscale level, the laser removes a first depth of a cross section of afirst ring-dyed yarn, leaving a first thickness of the first ring-dyedyarn remaining in a direction from an outer side of the fabric to abottom side of the fabric, for a second grayscale level, the laserremoves a second depth of a cross section of a second ring-dyed yarn,leaving a second thickness of the second ring-dyed yarn remaining in adirection from the outer surface of the fabric to the bottom of thefabric, the first grayscale level is a darker shade than the secondgrayscale level, the second depth is greater than the first depth, andthe first thickness is thicker than the second thickness.
 13. Thearticle of claim 11 wherein cross sections of a plurality of ring-dyedyarns of the article of clothing have total outer ring thicknesses of 22percent of a total thickness of the yarn with a variation of plus 5percent.
 14. The article of claim 11 wherein cross sections of aplurality of ring-dyed yarns of the article of clothing have total outerring thicknesses of 22 percent of a total thickness of the yarn with avariation of plus 10 percent.
 15. The article of claim 11 wherein crosssections of a plurality of ring-dyed yarns of the article of clothinghave outer ring thicknesses of 22 percent of a total thickness of theyarn with a variation of plus 15 percent.
 16. The article of claim 11wherein cross sections of a plurality of ring-dyed yarns of the articleof clothing have outer ring thicknesses of 22 percent of a totalthickness of the yarn with a variation of plus 20 percent.
 17. Thearticle of claim 11 wherein cross sections of a plurality of ring-dyedyarns of the article of clothing have outer ring thicknesses of 22percent of a total thickness of the yarn with a variation of plus 25percent.
 18. The article of claim 1 wherein the indigo ring-dyed yarncomprises an outer layer of cotton and an elastane core, wherein in across section of the indigo ring-dyed yarn, the outer ring surrounds theinner core, which surrounds the elastane core.
 19. The article of claim1 wherein the indigo ring-dyed yarn comprises a twists per inch in arange from 4.2 to 4.8.
 20. The article of claim 1 wherein the indigoring-dyed yarn comprising a cross section comprising a total ring dyethickness of the outer ring that is at least 22 percent and less than 25percent of a total thickness of the yarn is obtained through processingthe indigo ring-dyed yarn in a indigo dye solution having a pH in arange from 10.7 to 11.2.
 21. The article of claim 6 wherein the indigoring-dyed yarn comprising a cross section comprising a total ring dyethickness of the outer ring that is at least 22 percent and less than 30percent of a total thickness of the yarn is obtained through twistingthe yarn to be in a range from 4.2 to 4.8 twists per inch.
 22. Anarticle of clothing comprising: a fabric comprising indigo ring-dyedyarn, wherein the fabric comprises yarns that are ring dyed comprisingan outer ring, an inner ring, and inner core comprising elastane, theouter ring is indigo colored due to being penetrated through by theindigo dye while the inner ring is white or off-white colored due to notbeing penetrated to by the indigo dye; and a finishing pattern on thefabric, wherein the finishing pattern is formed by a laser removingselected amounts of material from the fabric, before lasering, a crosssection of a ring-dyed yarn comprises a generally round shape with dyedindigo fibers in the outer ring that surround the inner ring, whichsurrounds the inner core, after being exposed to the laser and the depthof material that has been removed, a cross section of the warp yarncomprises a region with a flattened shape relative to the generallyround shape before lasering, for lighter locations of the finishingpattern, a greater depth of the indigo ring-dyed yarn is removed,revealing a greater width of an inner core of the dyed yarn, relative todarker locations of the finishing pattern where a lesser depth of theindigo ring-dyed yarn is removed, revealing a lesser width of an innercore of the dyed yarn, and a cross section of a ring-dyed yarn comprisesa total ring dye thickness of the outer ring that is at least 24 percentand less than 25 percent of a total thickness of the yarn.